Relay



3 Sheets-Sheet 1 C. H. LARSON RELAY Filed Oct. 5. 1932 July 24, 1934.

` July 24, 1934. Q H LARSON 1,967,945

RELAY Filed Oct. 5, 1932 5 Sheets--Shee'fI 2 July 24, 1934.

C. H. LARSON RELAY Filed` OOC. 5. 1932 5 Sheets-Sheet 3 9 ELU/@702% j@0W/Elf Patented July 24, 1934 UNITED STATES.

RELAY Carl H. Larson,

Elkhart, Ind., assignor to The Adlake Company, a corporation of IllinoisApplication October 5, 1932, Serial No. 636,286

. 3 Claims.

determined standard. In railway signaling systems, they are placed atintervals along the line to place the signals in local circuit shouldthei power in the main line fall below the voltage required for clearsignals.

In transferring the load from one source of current to another, it isessential that the main circuit be broken before the local circuit` isestablished, and Vice versa when the main cirl cuit through the signalis reestablished. One object of the present invention, therefore, is toprovide a time delay element that will insure a breakage of one circuitbefore the completion of the other.

Other objects of the invention are to provide v 2 mercury switches totake the place of the mechanical contacts heretofore employed in rail-vway signaling systems; to provide a novel arrangement for mounting twoor more mercury switches on a single operating coil; and to provide arelay which will be simple in construction, but reliable in operation.

Further and other objects and advantages of the invention will becomeapparent as the disclosure proceeds and the description is read o' inconjunction with the accompanying drawings,

in which Fig. 1 is a diagrammatic illustration of a preferred embodimentof the invention in which mercury switches of the plunger type areemployed for making and breaking the circuits. The switches in this gureare shown with their plungers in the position they assume when the maincoil is energized.

Fig. 2 is a diagrammatic illustration correspending to Fig. 1 butshowing the plungers in the position they assume when the main coil isdeenergized;

Figs. 3, 4 and 5, are circuit diagrams showing various modifications ofthe invention;

Fig. 6 is a plan view showing the preferred arrangement of amulti-switch relay;

Fig. 7 is a vertical, sectional view of the relay shown in Fig. 6, takenon the line 7 7 of that figure.

Fig. 8 is a perspective view of the laminated core pieces; and

Figs. 9, 10 and 11 are perspective views of the plungers used in theseveral switches.

` But the specific illustration of preferred em-V bodiments of theinvention and the corresponding specific description that follows arefor the purpose of disclosure only and are not to be construed. aslimiting the scope of the appended claims except as required bythepriorart.

Referring rst to Figs. l and 2, a preferred embodiment of the relay hasbeen diagrammatically shown applied to a railway signal circuit. Arailway signal is indicated at 20 which is normally operated onalternating current derived from the secondary coil 21 of thetransformer 22, the primary coil 23 yof which is connected to 65 thepower line 24. A local battery 25 is provided for operating the signalupon failure of the alternating current, and in cases when thealternating current falls below a predetermined voltage.

Four mercury switches A, B, C, and D are mounted in cooperative relationwith an electromagnet 26, the coil 27 of which is energized by theprimary coil 23 of the transformer at periods determined by the positionof the control switch E. The winding 28 of the control switch is shuntedacross the primary coil 23 of the transformer by conductors 29 and 30,and consequently the strength of the magnetic eld which it produces isdependent upon the voltage in the power line 24.

The switches A, B, C, D and E are mercury switches of the plunger typecomprising glass envelopes 31 through the bottom of which suitableelectrodes are sealed. Plungers oat on the mercury 32 within theenvelopes, and determine by the amount of mercury they displace whichelectrodes are bridged by mercury. The switches are evacuated and thenfilled with an inertv gas as common in such constructions.

Springs 33 and 34 serve to protect the envelope from damage due to roughhandling of the switch.

The control switch E has electrodes 35 and 36 sealed through the bottomof the envelope, the former being protected by a glass insulating sleeve37 to a point 38, leaving the portion 39 of the electrode bare. Theelectrode 35 is connected by conductors 40 to one side of the coil 27,the other side of the coil being connected by a conductor 41 to themactrade se through the winding 100 28 of the control switch E. Sleeves42 and 43 of suitable magnetic material, such as Swedish iron, aremounted within the spool or core sleeve 44 of the control switch E andprovide an air gap 45 adapted to be closed by the plunger 46, also 105of magnetic material, when the coil is energized (as shown in Fig. 1).In this position of the plunger, sufficient mercury is displaced tocause the bared portion 39 of the electrode 35 to be covered withmercury, thus establishing electrical connection between the electrodes35 and 36 and energizing the main coil 27.

IJin case the Voltage in the `main line 24 falls below a predeterminedstandard, for example, be-

5 low 75 voltsv on a normal 110 volt alternating current line, thestrength of the magnetic field in the coil E is insuilcient-to hold theplunger 46 in depressed position against the buoyancy of the mercury andit will rise to the position shown in Fig. 2, breaking the circuitthroughthe main coil 27 and aiecting the switches A, B, C, and D,accordingly.

The switches A, B, C and D are operated by the main coil 27 by providinga pole piece 47 at the top of Ythe switches and a pole piece 48 at thebottom of the switches. The upper and lower pole sleeves 49 associatedwith each switch provide suitable air gaps 50, 51,52 and 53 for theswitches A, B, C, and D, respectively. The pole pieces and the polesleeves are made of suitable magnetic material.

Switches B and C are in the direct current circuit, the latter switchbeing slow acting-to insure that the alternating current circuit .willbe broken before the direct current circuit is made when the signal 20.is being transferred from alternating current to direct current.Electrodes 54and 55 of the switch B and electrodes 56 and 57 ofswitch Care connectedin series with the load 20 and the battery 25, as clearlyappears from the drawings. l

The electrodes 54 and 56 are insulated to a point adjacent the top ofthe electrode by a glass sleeve, as in the control switch E. The plunger58 of switch B assumes the position shown in Fig. l when the coil 27 isenergized, thus breaking the circuit through the battery. The plunger 59of 4switch C differs from plunger 58 of switch B in that it is closed atthe top except for a small opening 60. The closure is tapered, asindicated at -61m to prevent mercury from becoming lodged on top of theplunger.

When the plunger 59 is in the position shown in Fig. 1, the air gap 52is closed and the plunger is, preferably, completely lifted from themercury within the envelope. This causes the mercury level to fall belowand the direct current circuit is broken at a second point.

The electrodes 62 and 63 of switch A and electrodes 64 and 65 of switchD arer connected in series with the load 20 and the secondary coil ofthe transformer 22. The plunger 66 of switch A assumes the positionshown in Fig. l when the coil 27 is energized, thus covering theelectrode 62 with mercury and closing the alternating current circuit onthe one side of the load.

The plunger 67 of switch D normally is in the position shown in Fig. 1and in this position, the electrode 64 is covered with mercury,completing the alternating current circuit through the load.

It will thus be seen that under normal conditions, the control switch Eenergizes the main coil 27 and completes the alternating currentcircuitthrough the signal 20 by bridging electrodes 62 and 63, and 64 and 65 ofswitches A and D, respectively,`while holding the direct current circuitopen by breaking the connections between electrodes 54 and 55, and 56and 57 of switches B and C, respectively. If the power in the line24'falls below a predetermined voltage, say 75 yolts, the plunger 46 ofcontrol switch E, due to its buoyancy and the insuicient strength of themagnetic field, rises and uncovers the electrode 35. Immediatelythereupon the coil 27 is deen-- ergized and the plungers 66 and 67 ofswitches AA and D rise, due to their buoyancy, and the plungers 58 and59 of switches B and C fall, due to gravity.

Switches A and B being quick acting, will break and make theirconnections substantially instantaneously. The switch D will break thealternating current circuit at a second point shortly thereafter. SwitchC, however, delays the completion of the direct current circuit byforming a gas trap within the plunger 59 and allowing the gas Within theplunger to slowly escape through the vent 60.

In this way, the mercury is kept away from the electrode 56 even whenthe plunger is in the position shown in Fig. 2 until the pressure on theinside and outside of the plunger is equalized by the escape of gasthrough the Vent 60.

Conversely when the load is transferred from Y direct current toalternating current, which happens whenever the alternating current inline 24.picks up to some predetermined voltage, the plunger 46 incontrol switch E is again depressed into the mercury andthe main coil 27is energized, whereupon the direct current circuit is broken immediatelyat switch B and at substantially the same time at C (the plunger in thiscase being lifted completely out of the mercury and causing a quickerbreak than in switch D), and the alternating current is made by theaction of switches A and D, the latter switch providing a. sufficientinterval of time before closing the alternating current circuit toinsure that the direct current circuit is previously broken.

Referring now'to Figs. 3, 4 and 5, there has been illustrated threeadaptationsof the present invention to mechanical relays. Although ineach instance, theour electromagnetic switches which control the makingand breaking of the direct and alternating current circuits are shown asenergized by separate coils, it will be underftood that they may beenergized by a single coil if desired. As before, the referencecharacter 24 designates a source of alternating current connected to theprimary coil 23 of a transformer 22, the secondary A, B, C and. D, iscontrolled by switch E which in Fig. 3 is shunted across the primarycoil 23 of the transformer and in Figs. 4 and 5 is shunted across thesecondary coil ofA the transformer. Switches C and D are slow acting sothat switch C, before completing the direct current circuit provides aninterval of time to insure the operation of switch A, and switch Dbefore completing the alternating current circuit, provides4 an intervalof time to insure the operation of switch B.

Figs. 3 and 5 differ from each other only in that the control switch Ein the latter is connected across the secondary coil in the transformer,while in the former, it is connected across the primary coil.

Fig. 4 differs from Fig. 5 only in that the switch E is placed in thealternating current circuit of the signal, thus furnishing threeswitches in that circuit to insure proper breaking' of the circuitbefore the direct current circuit through the signal is made.

The function of switch E in Fig. 4 can be clearly understood byobserving that when the switch is energized, as shown in the figure,thecoils or switches A, B, C and D are connected in series with thesecondary coil of the transformer and at the same time the alternatingcurrent circuit through the signal 20 includes the armatures of switchesD, E and A.

The springs 68 associated with the armatures E, A and D, in Figs.3-5,inclusive indicate that the armatures are held held away from theirassociated contacts when the coils are deenergized and, therefore,correspond to the buoyancy of the mercury in the mercury switchadaptation of this invention. l

A further description of the embodiments of the invention shown in Figs.3-5 is believed unnecessary in view of the specic description of therelay shown in Figs. 1 and 2. It will be understood that the circuits ofFigs. 3, 4 and 5 are equally applicable to the mercury switch relay ofFigs. 1 and 2.

Figs. 6-11 inclusive illustrate certain of the.

physical characteristics of the mercury switch embodiment of thisinvention. As there shown, the coil 27 is wound upon a spool 69substantially square in cross section. L-shaped laminated core pieces 70are adapted to be placed in the spool in the manner shown in Fig. 6, thelong arms 71 of each core piece being offset at 72 to receive thecorrespondingly formed core piece which is inserted from the other endof the spool. The short arms 73 of the core pieces project radiallytoward the margin of the coil, as indicated in Fig. 6. Suitable metalclips 74 are used to clamp the pole sleeves 49 to the arm 73 landthrough these sleeves the mercury switches themselves are mounted.Rubber gaskets '75 are applied to the tops and bottoms of the switches,as shown in Fig. 7 to hold the switches rmly in place.

The coil 27, being operated on 'alternating current, has increasedeiliciency when the core pieces are laminated as shown.

It will be noted that the plungers in Figs. 9, 10 and 11 are providedwith either lugs or notched flared ends which space the plungers fromthe envelopes without interfering with the passing of mercury on theoutside of the plunger.

It Will be understood that the various coils, switch characteristics,etc. may be made to suit the particular conditions o'f service for whichthe relay is to be used, but by way of illustration, the coil 27, ifoperated on 10 volt A. C. may have 200 turns of 19 gauge enameled wirehaving a current consumption of 1.7 watts. The coil-of the controlswitch E under such conditions may have 1000 turns of No. 26 gaugeenameled wire with a current consumption of .3 of a watt. If the relayis operated at 110 volt A. C., as shown in Figs. 1-2, the coil foroperating the four switches may have 2300 turns of No. 29 gauge enameledwire drawing 1.75 watts. In such case, the control coil of the switch Ewould have 15,000 turns of No. 26 gauge enameled wire, consuming .3 of awatt.

What I claim is:

l. In combination,- a, primary circuit including a source of electricalenergy and a load, an auxiliary circuit including another source ofelectrical energy and the same load, means responsive to pressure in theprimary circuit for determining which of said circuits will operate theload, said means including a pair of independently operating circuitbreakers in the main circuit, one on each side of the load, and onebeing slow acting, and a like pair of circuit breakers in the auxiliarycircuit, also on opposite sides of the load, and one being slow acting,said slow acting circuit breakers in the primary and auxiliary circuitsserving to insure that the transfer of the load from one circuit to theother will be eiected without overlap.

2. In combination, a primary circuit, an auxiliary circuit, a loadadapted to be operated from either of said circuits, a fast acting relayand a slow acting relay in each circuit, means responsive to pressure inthe primary circuit for operating said relays, said slow acting relayspreventing an overlap in the circuits when a transfer is being made fromone to the other.

3. In combination, a primary circuit, an auxiliary circuit, a loadadapted to be operated from either of said circuits, a fast acting relayand a slow acting relay in each circuit, said relays comprisingvertically mounted switch envelopes having contacts hermetically sealedwithin the envelopes, mercury4 in the envelopes adapted to bemanipulated to make or break the circuit through the contacts andmagnetically controlled displacers for shifting the mercury, meansresponsive to pressure in the primary circuit for operating said relays,said slow acting relays preventing an overlap in the circuits when atransfer is being made from one to the other.

CARL H. LARSON.

